arm11: fix another infinite loop bug

reset init would get stuck in an infinite loop when
e.g. khz was too high. Added timeout. This is a copy
of paste of a number of such bugfixes in the arm11
code.

Arm11 code reviewed for further such infinite loop bugs
and I couldn't find any more. Xing fingers it's the last
one...

Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>